Circuit breaker



Get. 28,1930. 7 R. LoGsTADT EJ79 848 CIRCUIT BREAKER Filed Oct. 23, 1925 2 Sheets-Sheet 1 WITNESSES: INVENTOR Richard Loyszaaz. BY

ATTCSRNEY Oct. 28, 1930. R. LOGSTADT 1,779,848

CIRCUIT BREAKER Filed Oct. 23, 1925 2 Sheets-Sheet 2 Fig 3.

WITNESSES: 5 lNVENTOR Pic/vardbayszadz.

Patented Oct. 28, 1930 UNITED STATES PATENT OFFICE RICHARD LOGSTADT, F BERLIN-SCHONEBERG, GERMANY, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, OF NEW YORK, N. Y., A. CORPORA- TION OF NEW YORK CIRCUIT BREAKER My invention relates to circuit breakers and particularly to high-speed circuit breakers wherein the contact members are separated at relatively high speed in response to a predetermined overload or short-circuit condition.

An object of my invention is to provide a high-speed circuit breaker having an electromagnetically operated switch arm that is provided with a movable contact member which separates a greater distance from the stationary contact member than ordinarily will be occasioned by a certain movement of the actuating armature.

Another object of my invention is to provide a circuit breaker having the above-noted characteristics that may be either automatically or manually tripped to open position and which may automatically trip to open position regardless of the position of the manually operated mechanism.

Another object of my invention is to provide a high-speed circuit breaker that is simple in construction and effective in operation.

These and other objects that will be made apparent throughout the further description of my invention are attained by means of the circuit-breaker apparatus hereinafter described and illustrated in the accompanyin g drawings, wherein,

Fig. 1 is an elevational view of a circuit breaker embodying features of my invention and showing the parts in their full-open position.

Fig. 2 is an elevational view ratus shown in Fig. 1, showing in semi-closed position.

Fig. 3 is an elevational view ratns shown in Fig. 1, showing the parts in full-closed position, and

Fig. 4 is an elevational View of a modified form of circuit breaker showing the contact members in open position.

Referring to the drawings, the circuit breaker comprises an electromagnet 5 consisting of core member 6 having oppositely disposed legs or pole pieces 7 and 8 and a centrally disposed pole piece 9 about which is wound a potential coil 11. The switch of the appathe end parts of the appa- 1925, Serial No. 64,374, and in Germany October 24, 1924.

arm 12, consisting of two bars disposed on opposite sides of the core member 9, is pivoted for oscillation about a pivot pin 13. A

movable armature 14 is pivotally connectedto the switch arm 12 and moves between the extremities of the pole pieces 7 and 8. The armature is normally retained in the open position shown in Fig. 2 by the flux of the potential coil 11 and is rapidly moved into engagement with the pole piece 8 as shown in Fig. 1 by means of a current coil 15 surrounding the pole piece 8.

The switch contact members comprise a stationary contact member 16 and a movable contact member 17 that is rotatably mounted upon a pivot pin 18 carried by the upper end of the switch arm 12. A spring 19 connected at one end to the contact member 17 and at the other end to the switch arm 12 serves to normally move the contact member to the open position shown in Fig. 1, and a spring 21 connected at one end to the core member 6 and at the other end to the lower end of the switch arm 12 serves to normally move the switch arm to the open position.

The switch arm 12 is manually operated into closed position by means of an operating handle 22 provided with a pin 23, that operates in an elongated slot 24 in a rod 25 that is connected to the lo ver end of the switch arm 12 by means of a bell-crank lever 26 and a link 27. Upward movement of the handle 22 causes the switch arm to be rotated counterclockwise to the position shown in Fig. 2. This movement, however, does not occur until the operating handle 22 has moved a predetermined distance due to the pin-and-slot connection and after it has moved an operating arm 28 to its lowermost position, as shown in Fig. 2. A latch 29 is pivotally mounted on the arm 28 and the arm is connected to the operating handle 22 by means of a link 31.

When the latch 29 is in its lowermost position, a cross bar 32, which operates in slots 33 in the switch arm 12, engages a shoulder 34 on the latch 29. The cross bar 32 is carried by a link 35 pivotally connected to the contact I position shown in Fig. 2, downward movement of the operating handle 22 causes the operating arm 28 and latch 29 to be raised, thus causing the contact member 17 to be movedinto the closed position shown in Fig. 3 where it remains until the latch 29 is moved towards the left by the operating rod 36 or is automatically released by movement of the armature 14 and switch arm 12 to the right in response to an excessive current passing through the current coil 15.

Movement of the switch arm 12 to the right moves the cross bar 32 ofi of the shoulder 34 of the latch and permits the spring 19 -to move the contact member to the open position.

By reason of the movement of the contact member 17 with respect to the switch arm 12, the distance of separation of the cont-act members 16 and 17 is considerably increased over the distance that the switch arm 12 actually moves and, by reason of the combined opening movement of the switch arm and the contact member, the velocity of separation is increased.

In view of the foregoing, it will be seen that the circuit breaker comprises essentially an electromagnetically operated switch arm to which is pivoted a spring-actuated contact member which is so retained in operative position that it may be tripped to open position, shown in Fig. 1, either manually or automatically in response to predetermined conditions and which is free to move to open position re gardless of the position of the manually-operated mechanism.

Should the contact member 17 be moved to closed position during the presence of overload or short-circuit conditions, the flux due to the abnormal rush of current through current coil 15 will immediately cause the switch arm 12 to be actuated toward the right and thereby release the contact member 17 from the latch 29, with the result that the contact member will immediately be moved to open position by the spring 19.

In Fig. 4 I have illustrated a modified form of high-speed circuit breaker wherein both contact members are caused to move in opposite directions in response to overload or short-circuit conditions. The circuit breaker comprises an electromagnetic device 5 similar to the electromagnetic device illustrated in Figs. 1 to 3. That is, it is provided with a core member 6 having operatively disposed pole pieces 7 and 8 and a central pole piece 9 about which is mounted a potential coil 11. An armature 14 operates between the extremities of the pole pieces 7 and 8 and is normally retained in closed or its left-hand operative position by the flux in the pole pieces 7 and 9 and moved to the upper position into engagement with'the pole piece 8 by an abnormal current in the current coil 15.

Two switch arms 37 and 38 are pivotally mounted on the core member 36 and latched about pivot pins 39 and 41, respectively.

The switch arm 37 is normally yieldingly retained in open position by means of a spring 42 and is retained in the closed positlon indicated in broken lines by means of a pivotally mounted latch 43 that engages with a bar 44 on the lower end of the switch arm 37. The switch arm 38 is normall retained in the closed position shown in bro en lines by the flux through the pole pieces 7 and 9.

When an overload or short-circuit condition occurs, the armature 14 is rapidly turned clockwise, the lower end thereof striking the arm 45 of the latch 43 and causing it to release the switch arm 37 which is rapidly turned counter-clockwise by the spring 42. The switch arms 37 and 38 may be moved to closed position by means of links 46 and 47, respectively, which may be connected to manually operable trip free mechanism.

I claim as my invention:

1. Switch mechanism comprising a contact member, a movable support member, a second contact member carried by the support member and movable relatively thereto, and a latch between said support member and said second contact member for retaining the second contact member in engagement with the first contact member when the support member is in circuit-closing position.

2. Switch mechanism comprising a contact member, a movable support member, a second contact member carried by said support member and movable relativel thereto, and latching means for retaining t e second contact member fixed relative to said support member when the support member is in circuit-closing position.

3. Switch mechanism comprising an articulated member having a contact portion and a current-responsive portion for effecting opening movement of the contact portion in response to predetermined movement of the current-responsive portion, separate yielding means for moving the said portions to open position, current-responsive means for releasably retaining the current-responsive portion in closed position and a latch releasable by movement of the current-responsive portion for releasably retaining the contact portion in closed position.

4. Switch mechanism comprising a contact member, a current-responsive movable support member, a second contact member carried by the support member and movable relatively thereto, and means for retaining the second contact member fixed relative to said support member when the support member is in circuit-closing position and means tending to move said second contact member with respect to the support member in a direction away from said first contact member as said support member moves toward opencircuit position.

5. Switch mechanism comprising a contact member, a current-responsive movable support member, a second contact member carried by the support member and biased to move relatively thereto in a direction away from said first contact member, and means for retaining the second contact member in engagement with the first contact member when the support member is in closed-circuit position and permitting relative movement of the second contact member with respect to the support member when the latter moves toward open-circuit position.

6. An electric switch comprising a contact member pivoted to a movable member and biased relative thereto, an armature on the movable member, a magnetic circuit cooperating with the armature adapted to retain the movable member in closed-circuit position and to cause it to be moved therefrom to opencircuit position, and a mechanical releasing means for retaining the contact member in predetermined relation to the movable member.

7 An electric switch comprising a contact member pivoted to a movable member and biased relative thereto, an armature on the movable member, a magnetic circuit associated with one end of the armature to retain the pivoted member in circuit-closed position, a second magnetic circuit adapted to attract the armature under predetermined conditions away from the first said magnetic circuit and a mechanical releasing means for retaining said contact member in predetermined relation to said movable member.

8. A switch mechanism comprising a contact member and a support therefor that is movable relative thereto, a magnetic circuit for retaining the support in closed-circuit position, an operating device for moving the support into engagement with the magnetic circuit thereafter to positively rotate the contact member into circuit-closed position and releasable means between said operating device and said contact member.

9; A switch mechanism comprising a movable contact member and a support therefor that is movable relative thereto, a magnetic circuit for retaining the support in circuitclosed position, an operating device for moving the support into engagement with the magnetic circuit upon the upward movement thereof and engaging means associated with the operating device to positively rotate the contact member to closed position upon a downward movement of the operating device, the said engaging means being releasable from the operating device during the said movement of the latter.

10. An electric switch including a pair of contact members at least one of which is movable, an actuating arm, an armature associated with said arm, a magnetic circuit associated with said armature, releasable en- RICHARD LOGSTADT. 

